In the past, there has been proposed an LED lighting device including a driving circuit for a cooling device for cooling an LED used as a light source. For example, such an LED lighting device is disclosed in document 1 (JP 2011-150936 A).
The LED lighting device disclosed in this document 1 includes: a DC power source; a series circuit connected between output terminals of the DC power source and constituted by connecting a plurality of LEDs; and a cooling device driver for dissipating heat generated by the LEDs. The cooling device driver is connected in parallel with at least one LED of the series circuit. Thus, a DC voltage developed across the at least one LED of the series circuit is supplied to the cooling device driver.
However, in the future, an output of an LED is expected to be more increased. Such an increase would cause an increase in a forward current supplied, and also cause an increase in a forward current supplied to an LED for providing power for the cooling device. Hence, according to the prior art, it is necessary to use an LED able to resist an increase in a forward current as the LED for providing power for the cooling device. This causes an increase in a production cost.
In addition, when a plurality of high power LEDs are employed, a metal member such as a heat dissipation member (e.g., a heatsink) for dissipating heat of the LEDs is necessary. In some cases, a cooling device for cooling the heat dissipation member is needed. Further, when a plurality of light sources constituted by LEDs are employed, each light source requires a cooling device. However, such lighting fixtures to be used may have different structures and different heat dissipation structures. This causes a disadvantage that it is necessary to design an optimal configuration of a power source circuit for a cooling device for each lighting fixture.